Abstract: A machine tool having a separately replaceable tool post is provided. The machine tool includes supports that are facing each other with an axis line of a main axis in an axial direction therebetween; a rotation tool post detachably connected on one of the supports and rotatable with respect to a first direction perpendicular to the axis line; a fastening member detachably connecting the rotation tool post on the one of the supports, wherein the rotation tool post includes: a rotation unit configured to rotate in the first direction on the one of the supports; an upper fastening unit at an upper portion of the rotation unit, and detachably fastened to the one of the supports; and a lower fastening unit at a lower portion of the rotation unit, and detachably fastened to the one of the supports so that the rotation unit is rotatable.